From: Julien Thierry <jthierry@redhat.com>
Date: Fri, 27 Mar 2020 15:28:47 +0000
Subject: objtool: Support multiple stack_op per instruction
Git-commit: 65ea47dcf4f936987a5fbf839c97acea00f4f196
Patch-mainline: v5.8-rc1
References: bsc#1202396
Instruction sets can include more or less complex operations which might
not fit the currently defined set of stack_ops.
Combining more than one stack_op provides more flexibility to describe
the behaviour of an instruction. This also reduces the need to define
new stack_ops specific to a single instruction set.
Allow instruction decoders to generate multiple stack_op per
instruction.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200327152847.15294-11-jthierry@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
tools/objtool/arch.h | 4 +++-
tools/objtool/arch/x86/decode.c | 13 ++++++++++++-
tools/objtool/check.c | 32 +++++++++++++++++++++++++-------
tools/objtool/check.h | 2 +-
4 files changed, 41 insertions(+), 10 deletions(-)
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -70,6 +70,7 @@ struct op_src {
struct stack_op {
struct op_dest dest;
struct op_src src;
+ struct list_head list;
};
void arch_initial_func_cfi_state(struct cfi_state *state);
@@ -77,7 +78,8 @@ void arch_initial_func_cfi_state(struct
int arch_decode_instruction(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int maxlen,
unsigned int *len, enum insn_type *type,
- unsigned long *immediate, struct stack_op *op);
+ unsigned long *immediate,
+ struct list_head *ops_list);
bool arch_callee_saved_reg(unsigned char reg);
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -81,13 +81,15 @@ bool arch_callee_saved_reg(unsigned char
int arch_decode_instruction(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int maxlen,
unsigned int *len, enum insn_type *type,
- unsigned long *immediate, struct stack_op *op)
+ unsigned long *immediate,
+ struct list_head *ops_list)
{
struct insn insn;
int x86_64, sign;
unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0,
rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0,
modrm_reg = 0, sib = 0;
+ struct stack_op *op;
x86_64 = is_x86_64(elf);
if (x86_64 == -1)
@@ -128,6 +130,10 @@ int arch_decode_instruction(struct elf *
if (insn.sib.nbytes)
sib = insn.sib.bytes[0];
+ op = calloc(1, sizeof(*op));
+ if (!op)
+ return -1;
+
switch (op1) {
case 0x1:
@@ -474,6 +480,11 @@ int arch_decode_instruction(struct elf *
*immediate = insn.immediate.nbytes ? insn.immediate.value : 0;
+ if (*type == INSN_STACK)
+ list_add_tail(&op->list, ops_list);
+ else
+ free(op);
+
return 0;
}
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -282,6 +282,7 @@ static int decode_instructions(struct ob
}
memset(insn, 0, sizeof(*insn));
INIT_LIST_HEAD(&insn->alts);
+ INIT_LIST_HEAD(&insn->stack_ops);
clear_insn_state(&insn->state);
insn->sec = sec;
@@ -291,7 +292,7 @@ static int decode_instructions(struct ob
sec->len - offset,
&insn->len, &insn->type,
&insn->immediate,
- &insn->stack_op);
+ &insn->stack_ops);
if (ret)
goto err;
@@ -673,6 +674,7 @@ static int handle_group_alt(struct objto
}
memset(fake_jump, 0, sizeof(*fake_jump));
INIT_LIST_HEAD(&fake_jump->alts);
+ INIT_LIST_HEAD(&fake_jump->stack_ops);
clear_insn_state(&fake_jump->state);
fake_jump->sec = special_alt->new_sec;
@@ -1317,10 +1319,11 @@ static bool has_valid_stack_frame(struct
return false;
}
-static int update_insn_state_regs(struct instruction *insn, struct insn_state *state)
+static int update_insn_state_regs(struct instruction *insn,
+ struct insn_state *state,
+ struct stack_op *op)
{
struct cfi_reg *cfa = &state->cfa;
- struct stack_op *op = &insn->stack_op;
if (cfa->base != CFI_SP && cfa->base != CFI_SP_INDIRECT)
return 0;
@@ -1410,9 +1413,9 @@ static void restore_reg(struct insn_stat
* 41 5d pop %r13
* c3 retq
*/
-static int update_insn_state(struct instruction *insn, struct insn_state *state)
+static int update_insn_state(struct instruction *insn, struct insn_state *state,
+ struct stack_op *op)
{
- struct stack_op *op = &insn->stack_op;
struct cfi_reg *cfa = &state->cfa;
struct cfi_reg *regs = state->regs;
@@ -1426,7 +1429,7 @@ static int update_insn_state(struct inst
}
if (state->type == ORC_TYPE_REGS || state->type == ORC_TYPE_REGS_IRET)
- return update_insn_state_regs(insn, state);
+ return update_insn_state_regs(insn, state, op);
switch (op->dest.type) {
@@ -1752,6 +1755,21 @@ static int update_insn_state(struct inst
return 0;
}
+static int handle_insn_ops(struct instruction *insn, struct insn_state *state)
+{
+ struct stack_op *op;
+
+ list_for_each_entry(op, &insn->stack_ops, list) {
+ int res;
+
+ res = update_insn_state(insn, state, op);
+ if (res)
+ return res;
+ }
+
+ return 0;
+}
+
static bool insn_state_match(struct instruction *insn, struct insn_state *state)
{
struct insn_state *state1 = &insn->state, *state2 = state;
@@ -1996,7 +2014,7 @@ static int validate_branch(struct objtoo
return 0;
case INSN_STACK:
- if (update_insn_state(insn, &state))
+ if (handle_insn_ops(insn, &state))
return 1;
break;
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -51,7 +51,7 @@ struct instruction {
struct instruction *first_jump_src;
struct list_head alts;
struct symbol *func;
- struct stack_op stack_op;
+ struct list_head stack_ops;
struct insn_state state;
struct orc_entry orc;
};